Method and apparatus for determining  base station identity

ABSTRACT

Methods for improving the time to acquire an identity of a base station by a mobile station, by relying on locally-unique attributes of the base stations instead of globally-unique attributes of the base stations, are presented. In some embodiments, data may be requested, the data may contain a globally unique attribute of a base station, a first locally unique attribute of the base station, and a second locally unique attribute of the base station. In some embodiments, data may be received in response to the request, the data may contain at least the first locally unique attribute and the second locally unique attribute. It may then be determined that the data did not contain the globally unique attribute, and an identity of the base station based at least in part on the first locally unique attribute and the second locally unique attribute may be acquired.

CROSS REFERENCES

This application is a continuation of U.S. patent application Ser. No.13/657,676, filed Oct. 22, 2012, Attorney Docket No. 120807. Thisapplication is hereby incorporated by reference for all purposes.

BACKGROUND

Wireless communications systems traditionally rely on satellites withina line of sight in order to obtain a positioning and timing information.However, wireless communications systems may rely increasingly onterrestrial base stations in order to assist in acquiring informationabout the location of satellites or other timing information. Improvingupon these techniques may relate to improving signal acquisition time ofa satellite or base station, reducing the power consumed when acquiringthese data, or improving the accuracy of identification of satellites orbase stations. It may be desirable to create techniques or systems thatimprove on any or all of these characteristics.

SUMMARY

In embodiments of the invention, these aforementioned problems and otherproblems may be solved according to the disclosures provided herein.

Methods, apparatuses, systems and computer-readable media for improvingthe time to acquire an identity of a base station, by relying onlocally-unique attributes of the base stations instead ofglobally-unique attributes of the base stations, are presented.

In some embodiments, data containing a globally unique attribute of abase station, a first locally unique attribute of the base station, anda second locally unique attribute of the base station may be requested.An example of a globally unique attribute of a base station may be acell ID (CID) value of the base station. An example of a first and asecond locally unique attribute may be a cell parameter ID (CPID) and aprimary frequency (PF) value of the base station. Data may be receivedin response to the request, the data containing at least the firstlocally unique attribute and the second locally unique attribute. Insome embodiments, it may be determined that the data did not contain theglobally unique attribute, and then an identity of the base stationbased at least in part on the first locally unique attribute and thesecond locally unique attribute may be acquired.

In some embodiments, a database containing reference globally uniqueattributes and reference locally unique attributes may be maintained.Data in the database may be in the form of a “triplet,” each triplet maycontain a reference globally unique attribute and a first and secondreference locally unique attribute. A first locally unique attribute anda second locally unique attribute may be compared to values in thedatabase. These values may be associated with reference and/or localbase stations.

In some embodiments, the database may be periodically purged, updated,and/or refreshed. Items in the database may be purged after havingremained in the database a predetermined length of time. Items may beupdated based on data received from base stations in geographicproximity to a device containing the database, such as a mobile station.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of variousembodiments may be realized by reference to the following figures. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 is an example multiple access wireless communication systemaccording to some embodiments.

FIG. 2 is an example wireless communications interface including atransmitter system and a receiver system according to some embodiments.

FIG. 3 is an example wireless communications environment of a userequipment (UE) according to some embodiments.

FIG. 4 is an example scenario of a mobile station traveling through theranges of multiple base stations according to some embodiments.

FIG. 5A shows exemplary message formats according to some embodiments.

FIG. 5B shows other exemplary message formats according to someembodiments.

FIG. 5C is an example database of some embodiments.

FIG. 6 is an exemplary flowchart showing methods of some embodiments.

FIG. 7 is an example computer system according to some embodiments.

DETAILED DESCRIPTION

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments or designs.

The term “globally unique attribute” may refer to an attribute, value,identifier or marker that is unique globally, in the sense thatreference to a globally unique attribute unambiguously refers to onlyone entity in the entire world. Examples of globally unique attributesmay include IP addresses for devices configured to access the Internet,Vehicle Identification Numbers (VINs) for vehicles, internationaltelephone numbers and cell Identification (CID) values for terrestrialbase stations.

The term “locally unique attribute” may refer to an attribute, value,identifier or marker that is unique locally, in the sense that there maybe duplicates of the same locally unique attribute and thus reference toa locally unique attribute may identify only a local entity withoutambiguity. Examples of a locally unique attribute may include streetaddresses, student ID numbers, city names, and cell parameter IDs(CPIDs) and primary frequency values of terrestrial base stations.

The techniques described herein may be used for various wirelesscommunication networks such as Code Division Multiple Access (CDMA)networks, Time Division Multiple Access (TDMA) networks, FrequencyDivision Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA)networks, Single-Carrier FDMA (SC-FDMA) networks, etc. The terms“networks” and “systems” are often used interchangeably. A CDMA networkmay implement a radio technology such as Time Division Synchronous CodeDivision Multiple Access (TD-SCDMA), Universal Terrestrial Radio Access(UTRA), CDMA2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and Low ChipRate (LCR). CDMA2000 covers IS-2000, IS-95 and IS-856 standards. A TDMAnetwork may implement a radio technology such as Global System forMobile Communications (GSM). An FDMA network may include UniversalMobile Telecommunications System—frequency-division duplexing (UMTS-FDD)and the like. An OFDMA network may implement a radio technology such asEvolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20,Flash-OFDM®, etc. UTRA, E-UTRA, and GSM are part of Universal MobileTelecommunication System (UMTS). Long Term Evolution (LTE) is a releaseof UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are describedin documents from an organization named “3rd Generation PartnershipProject” (3GPP). CDMA2000 is described in documents from an organizationnamed “3rd Generation Partnership Project 2” (3GPP2). These variousradio technologies and standards are known in the art.

Single carrier frequency division multiple access (SC-FDMA), whichutilizes single carrier modulation and frequency domain equalization isa technique. SC-FDMA has similar performance and essentially the sameoverall complexity as those of OFDMA system. SC-FDMA signal has lowerpeak-to-average power ratio (PAPR) because of its inherent singlecarrier structure. SC-FDMA has drawn great attention, especially in theuplink communications where lower PAPR greatly benefits the mobileterminal in terms of transmit power efficiency. It is currently aworking assumption for uplink multiple access scheme in 3GPP Long TermEvolution (LTE), or Evolved UTRA.

Various embodiments are described herein in connection with an accessterminal. An access terminal can also be called a system, subscriberunit, subscriber station, mobile station, mobile, remote station, remoteterminal, mobile device, user terminal, terminal, wireless communicationdevice, user agent, user device, or user equipment (UE). An accessterminal can be a cellular telephone, a cordless telephone, a SessionInitiation Protocol (SIP) phone, a wireless local loop (WLL) station, apersonal digital assistant (PDA), a handheld device having wirelessconnection capability, computing device, or other processing deviceconnected to a wireless modem. Moreover, various embodiments aredescribed herein in connection with a base station. A base station canbe utilized for communicating with access terminal(s) and can also bereferred to as an access point, Node B, Evolved Node B (eNodeB), accesspoint base station, or some other terminology.

In some embodiments, the time to acquire an identity of local basestations may be improved, by relying on locally-unique attributes of thebase stations instead of globally-unique attributes of the basestations. During high traffic volume, a mobile station may be unable toreceive globally-unique attributes of a local base station, preventingthe mobile station from identifying the local base station underconventional means. An exhaustive search for any base stations may thenneed to be performed under conventional means, but the signalacquisition time may be improved over performing an exhaustive search,by relying on locally-unique attributes of nearby base stations whenglobally-unique attributes have not been obtained.

Acquiring the identity of local base stations may be important forvarious reasons. For example, a mobile station may rely on local basestations for global positioning and timing information in the event thatsatellites are not sufficiently in view with the mobile station. Asanother example, local base stations may be used in cellphonecommunications. Acquiring the identity of local base stations quicklyand efficiently may help a mobile station maintain continuous reception,so as to prevent dropped calls, for example. Additionally, achievingthese ends in an efficient manner may reduce power consumption as wellas save time. Embodiments described herein may help achieve any and allof these benefits.

Referring to FIG. 1, a multiple access wireless communication systemaccording to some embodiments is illustrated. An access point (AP) 100includes multiple antenna groups, one including 104 and 106, anotherincluding 108 and 110, and an additional including 112 and 114. In FIG.1, only two antennas are shown for each antenna group, however, more orfewer antennas may be utilized for each antenna group. Access terminal116 (AT) is in communication with AP 100 via antennas 112 and 114, whereantennas 112 and 114 transmit signals to access terminal 116 overforward link 120 and receive signals from access terminal 116 overreverse link 118. Access terminal 122 is in communication with AP 100via antennas 106 and 108, where antennas 106 and 108 transmit signals toaccess terminal 122 over forward link 126 and receive signals fromaccess terminal 122 over reverse link 124. In a Frequency DivisionDuplex (FDD) system, communication links 118, 120, 124 and 126 may usedifferent frequencies for communication. For example, forward link 120may use a different frequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access point. Insome embodiments, antenna groups each are designed to communicate toaccess terminals in a sector of the areas covered by access point 100.

In communication over forward links 120 and 126, the transmittingantennas of access point 100 utilize beamforming in order to improve thesignal-to-noise ratio of forward links for the different accessterminals 116 and 124. Also, an access point using beamforming totransmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access point transmitting through a single antenna to all its accessterminals.

FIG. 2 is a block diagram of an embodiment of a transmitter system 210of an access point and a receiver system 250 of an access terminal in amultiple-input and multiple-output (MIMO) system 200. At the transmittersystem 210, traffic data for a number of data streams is provided from adata source 212 to a transmit (TX) data processor 214.

In some embodiments, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides NT modulationsymbol streams to NT transmitters (TMTR) 222 a through 222 t, where NTis a positive integer associated with transmitters described in FIG. 2.In certain embodiments, TX MIMO processor 220 applies beamformingweights to the symbols of the data streams and to the antenna from whichthe symbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. NTmodulated signals from transmitters 222 a through 222 t are thentransmitted from NT antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby NR antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r, where NR is a positive integer associated with receiversdescribed in FIG. 2. Each receiver 254 conditions (e.g., filters,amplifies, and downconverts) a respective received signal, digitizes theconditioned signal to provide samples, and further processes the samplesto provide a corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the NR receivedsymbol streams from NR receivers 254 based on a particular receiverprocessing technique to provide NT “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion. Memory 272stores the various pre-coding matrices that are used by processor 270.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage. Processor 230 obtains the pre-coding matrices from memory 232,which stores various pre-coding matrices. Memory 232 may also containother types of data, such as information databases and locally andglobally unique attributes of multiple base stations.

Referring to FIG. 3, in some embodiments, a user equipment (UE) 302 mayoperate within a wireless network environment 300. A UE 302 may refer toany apparatus used and/or operated by a user or consumer, such as amobile device, cell phone, electronic tablet, touch screen device,radio, GPS device, etc. A UE or mobile station (e.g. a cell phone) 302may attempt to determine its global position or access globalpositioning information for other purposes, utilizing satellites 308and/or 310 to do so. The mobile station 302 may also rely on receivingdata from nearby terrestrial base stations 304 and/or 306, not justsatellites 308 and/or 310, particularly when the mobile station 302 haslimited visibility to the sky and satellites 308 and/or 310 due tomountain ranges 312, tall buildings, 314, crowded areas, etc.

To improve the time needed to acquire position information from localbase stations 304 or 306—and thus improve the time delay in determiningthe mobile station's 302 global position—the mobile station 302 maystore in memory a globally unique identification number of each basestation that the mobile station may typically use, e.g. base stations304 and 306. This globally unique identification number may be referredto as the cell ID (CID) of a base station. Each base station in theworld has a unique CID, thereby allowing a mobile station 302 toidentify exactly which base station is being accessed just by knowingthe CID. Remembering the CIDs of often-used base stations, e.g. 304 and306, allows the mobile station 302 to easily acquire signals of thosebase stations 304 and 306, reducing the time spent exhaustivelysearching for base station signals. Base stations may typically transmittheir CID automatically, as part of header information broadcasted sothat any UE 302 within range has an opportunity to receive theinformation. In this case, UE 302 may receive the globally unique CID ofbase station 304 via wireless signal 316, and UE 302 may receive theglobally unique CID of base station 306 via wireless signal 318.

However, referring to FIG. 4, some wireless communications environments(e.g. air interfaces, e.g. TD-SCDMA, UMTS-FDD, LTE, CDMA, etc.), whichgovern the types and format of data capable of being sent between mobilestations and base stations, do not require the CID to be transmitted tothe mobile station in certain circumstances, such as when the mobilestation experiences high traffic volume. This may be a problemparticularly when a mobile station passes beyond the range of one basestation into the range of another (e.g. handover situations) and thusneeds to identify the next base station.

For example, in wireless environment 400, a mobile station 402 maytravel through the ranges of various base stations 404, 406, and 408.The mobile station 402 may be travelling in a car or a train or throughsome other means. The rings around base stations 404, 406, and 408indicate how far the base stations may be able to provide reception oftheir respective transmissions. The arrow 410 may indicate the path thatmobile station 402 may travel, perhaps on a road or on train tracks orthe like. As mobile station 402 travels along the path 410, it can beseen that mobile station 402 will pass through the range first of basestation 406, fall out of range of base station 406 and into the range ofbase station 404. Then mobile station 402 will travel out of the rangeof base station 404 and into the range of base station 408.

The mobile station 402 may automatically seek access of another basestation as it loses reception of a current base station. This process ofswitching from one base station to the next, e.g. the switching of basestations described above, may be referred to as “handovers.” Duringhandovers, the mobile station 402 may acquire information allowing it todetermine a globally unique identification number of a local basestation currently in range, such as the CID. However, in certaincircumstances, e.g. high traffic volume situations, some wirelesscommunications environments, such as TD-SCDMA and UMTS-FDD, may notrequire the CID to be received by the mobile device. Thus, the CID of anew base station may not be identified during handover situations, e.g.when traveling along path 410, when mobile station 402 is used in a hightraffic volume situation. If the CID is not identified due to heavytraffic or for other reasons, then the mobile station 402 cannot rely onthe CID to identify the next base station and according to conventionalmeans must instead perform an exhaustive search to find the next basestation, causing significant time delay and loss in energy resources. Itmay be desirable then to have an alternate method for quickly acquiringbase stations when a mobile station 402 crosses between base stationboundaries.

Referring to FIG. 5A, according to some embodiments however, a mobilestation may receive two other pieces of data, e.g. a first locallyunique base station identification sometimes called a midamble index orcell parameter ID (CPID) and a second locally unique base stationidentification sometimes called a cell frequency parameter or primaryfrequency (PF), in order to determine what base stations are near to themobile station when the mobile station does not receive the globallyunique CID from the nearby base station. This general technique may beespecially useful in air interfaces such as TD-SCDMA and UMTS-FDD,standards which may not require a CID to be transmitted to the mobilestation during traffic.

Diagram 500 may illustrate example message formats and descriptions of aglobally unique attribute 502, e.g. a Cell Identity or CID, a firstlocally unique attribute 504, e.g. a midamble index or cell parameter ID(CPID), and a second locally unique attribute 506, e.g. a primaryfrequency (PF) of a base station. The CID may be considered a globallyunique attribute because each base station in the world is labeled witha unique CID, such that any particular CID unambiguously refers to onlyone base station in the world. A CPID and a PF together may beconsidered locally unique attributes of a base station because thevalues of a CPID and PF may repeat for other base stations, such thatvalues of a CPID and PF may only help identify base stations in a localarea.

Exemplary CID format 502 may show some attributes of a CID, and byextension a globally unique attribute according to some embodiments.Here, the format of a CID may be a bit string of 28 characters. In someembodiments, a character may be any number or letter. In otherembodiments, a character may be a hexadecimal value. The format may beglobally unique in that no CID value is the same, and thus a match of aCID may signal an identification of that particular base stationbelonging to that particular CID.

Exemplary CPID format 504 may show a format for a locally uniqueattribute having integer values ranging only from 0 to 127. It may beknown, therefore, that base stations having a particular CPID value mayhave overlapping matches to other base stations, since there are manymore than just 128 base stations installed around the world.

Exemplary PF format 506 may show a format for another locally uniqueattribute having integer values ranging from 0 to 16383. Here, giventhat there is a greater range of values than exemplary format 504, thecombination of the both values, as a first locally unique attribute anda second locally unique attribute, may help to more definitivelydetermine a base station even without receiving the globally uniqueattribute.

Referring to FIG. 5B, exemplary message format 525 may illustrate wherein a data stream the global and local unique attributes may be found. Asignal received by a mobile device in an air interface may be dividedinto 10 millisecond (ms) frames 527. Within each frame 527, there may betwo 5 ms sub frames 529. Within each subframe, there may be 7 time slots(TSs), each TS containing a specific set of information organized in aparticular pattern, with an 8^(th) time slot used to contain informationorganized in a completely different pattern. Here, TS0 531 may containdownlink information, as signified by the arrow pointing down. Downlinkinformation may be information received by a mobile station that istransmitted from a base station. TS0 531 may contain a globally uniqueattribute, such as a CID, and a locally unique attribute, such as a PF,in some embodiments. The next time slot may not be consistent withsimilar patterns of the other time slots, and may contain a downlinkpilot slot (DwPTS) 533, a gap (GP), and an uplink pilot slot (UpPTS)535. Uplink may refer to information transmitted by the mobile stationthat is received at a base station. The next six time slots 537 athrough 537 f may contain either downlink (DL) information or uplink(UL) information. In this example, three TSs 537 a, 537 b, and 537 c,are designated for UL, and three TSs 537 d, 537 e, and 537 f, aredesignated for DL. Each of these TSs may be subdivided according to thesame message format as shown. For example, the TS may contain a datapayload portion 539, followed by a midamble index 541, followed byanother data portion 539, and then a gap. In some embodiments, a TS mayrepeat the aforementioned format 16 times. This format may repeat foreach of the TSs 537 a through 537 f. The midamble index 541 may be alocally unique attribute of the base station transmitting suchinformation. The descriptions of FIG. 5B may be consistent with at leastsome air interfaces known in the art, such as TD-SCDMA. In otherembodiments, other message formats may be used according to other airinterfaces known in the art, and embodiments are not so limited.

Referring to FIG. 5C, an exemplary database 550 to store the globallyunique attribute and first and second locally unique attributes of basestations is described according to some embodiments. Database 550 maycontain at least three database items per entry, one item for each ofthe globally unique attribute 552, and first and second locally uniqueattributes, 554 and 556, respectively. In some embodiments, otherentries may exist, such as a geographic location entry 558. Database 550may be stored in memory of a mobile device, such as mobile device 402,UE 302, mobile station 116, mobile station 122, or access terminal 250.A mobile device storing database 550 may be configured to updatedatabase 550 whenever a new base station, or a different attribute ofthe base station, is received. The mobile device may obtain theinformation to populate the data 550 from signals received consistentwith message format 525 and formats 502, 504, and 506, for example. Forexample, base station entry 560 shows 4 entries: CID value 0x210a84c,CPID value 71, PF value 10055, and geographic location(E135.21°,N50.44°). Thus, if the mobile device receives just the CPIDand PF values, the location of the base station and/or the CID value maybe identified by referring to the entries in the same row.

In some embodiments, a database like exemplary database 550 may beupdated in the following manner: 1. Receive CID information from a basestation. The information may be obtained within signals consistent withmessage format 525 or other similar formats. 2. Receive CPID and PF infofrom same base station, through format 525 or other similar messageformats. 3. Update all entries for this base station. The entries may beupdated in a database 550 or something similar. Thus the globally uniquevalue is associated with two locally unique values. 4. Continue toupdate values of any whenever new info is received. 5. Check againstcurrent info found in signals received from base stations to see ifvalues need updating.

In some embodiments, the database may contain “triplets” of data,including a CID, PF, and CPID of a base station, in an exemplary format{CID_(i), PF_(i), CPID_(i}), where i is an index of a base station. Insome cases, embodiments that attempt to refer to and/or update database550 may not receive all the information in the triplet. For example, themobile device containing database 550 may be in dedicated traffic modewhile in some wireless environments, e.g. TD-SCDMA or UMTS-FDD, and thusmay not receive a globally unique attribute, e.g. a CID, when in contactwith a local base station. In such cases, the database 550 may not befully updated, and additionally the identity of a local base station maybe inferred using pre-existing information in the database 550.

As noted previously, a difference between conventional techniques andtechniques of some embodiments may be that the CPID and PF are notglobally unique values for base stations; they are only locally unique,meaning that the CPID and PF values may be repeated for other basestations in other locations. Therefore, a database, e.g. database 550,storing CPID 554 and PF 556 values may be refreshed periodically in thecase that some database items repeat local attributes or some of theinformation becomes inaccurate. To refresh the database, someembodiments may purge some or all entries in order to create space forfresh data. A complete purge of data may be beneficial when the mobilestation is activated in a completely different geographic location thanpreviously. For example, a user of the mobile station may go on vacationto another continent, and may still use the same mobile station. Theuser may then be in proximity to a completely different set of basestations having different locally unique attributes as well as differentglobally unique attributes.

Referring to FIG. 6, flowchart 600 represents an exemplary methodologyaccording to some embodiments. Starting at block 602, a database may bemaintained, the database may contain data of base stations, including aglobally unique attribute and at least one locally unique attribute ofeach base station. In some embodiments, the database may contain aglobally unique attribute, a first locally unique attribute and a secondlocally unique attribute for each base station entry. In someembodiments, the database may contain triplets of data, for example aCID, PF, and CPID of a base station, in an exemplary format {CID_(i),PF_(i), CPID_(i}), where i is an index of a base station.

The database may be consistent with the exemplary database described inFIG. 5B, but certainly other databases may be maintained. Maintainingthe database may involve updating values or entries of the database whenany globally unique or locally unique attributes are received, includingfor example, CID, PF, and/or CPID values. Maintaining the database mayalso involve refreshing and/or purging the database when values areinaccurate and/or too old. As previously mentioned, certain values, suchas the PF and CPID values, may be viewed as locally unique attributes oflocal base stations, and thus may change periodically depending on thelocation of the mobile station containing the database or for otherreasons. Updating and/or refreshing the database may be consistent withany of the techniques described herein.

At block 604, data may be received, the data may contain at least onelocally unique attribute of a base station. The data may be in referenceto a nearby base station that is within range of a mobile stationcontaining the database. The data may also contain more than just the atleast one locally unique attribute. For example, the data may contain aglobally unique attribute of the base station, a first locally uniqueattribute and a second locally unique attribute of the base station. Inother cases, the data may include any of the data described in FIG. 5A.Prior to block 604, a request may also be initiated to receive suchdata, the request being directed to nearby base stations that are inrange. In some embodiments the PF and CPID values of a local basestation may be received. In some embodiments, CID values from the localbase station may also be received. In some cases, a globally uniquevalue may not be received, because a mobile device according to someembodiments may be operating in a high traffic volume state and may bein a wireless communications network that does not allow the globallyunique value to be received while in the high traffic volume state. Forexample, a mobile device performing the methods described herein may beoperating in accordance with a SC-TDMA or UMTS-FDD environment.

At block 606, it may be determined if a globally unique value is presentin the received data from block 604. As previously mentioned, in somecases a globally unique value may not be present in the received databecause embodiments may be operating in a state that does not receivethe globally unique values in some circumstances. For example, theglobally unique value may not be received at a mobile station while inan SC-TDMA or UMTS-FDD environment when the mobile device is in a hightraffic volume state, e.g. placing a call. In some embodiments, it maybe determined whether the CID of a local base station is present in thereceived data.

Determining whether a globally unique attribute is present in thereceived data may be beneficial in cases where a mobile station needs toor desires to obtain the identity of a local base station. This may beuseful in a variety of cases, one example being when a mobile stationneeds to switch reception from one local base station to another in ahandover situation. Such handovers may be consistent with the scenariodescribed in FIG. 4.

At block 608, if it is determined that the globally unique attribute ofa local base station is present in the received data, then embodimentsmay be able to determine the identity of the local base usingconventional techniques. For example, if it is determined that the CIDof a local base station is present in the received data, the local basestation may be identified using the CID. This may be possible because aCID value is associated with only one base station in the entire world,and thus the base station may be accurately identified after knowing theCID value.

At block 610, if it is determined at block 606 that a globally uniqueattribute is not present in the received data, then the mobile devicemay identify a local base station based on the received locally uniqueattributes. The received locally unique attributes may be compared withvalues in the database. For example, the received PF and PCID values maybe compared to the reference PF and PCID values in the database.

At block 612, it may then be determined if the received locally uniqueattributes match any values in the database. Since the database may be acollection of base station attributes most commonly used or morerecently used, it may be likely the received locally unique attributesmatch some of the database values. For example, if a mobile stationtravels around one city most of the time, then the same local basestations around the city may be used most often. Therefore, if locallyand globally unique attributes of these base stations are stored in thedatabase, then there is a better chance that received locally uniqueattributes may be associated with one of the commonly used base stationsaround the city. Thus, even if the globally unique attribute is notreceived, the nearest base station needed to participate in handoversituations may still be determined.

At block 614, if the locally unique attributes match values in thedatabase, the identity of the local base station from where the datacame from may be acquired, using the received locally unique attributes.At least one inference may be made to determine which local base stationthe data came from. For example, if the received first and secondlocally unique attributes match values in the same row k of thedatabase, then it may be inferred that the local base station is thebase station associated with the CID of row k.

In other cases, the first received locally unique attribute may match avalue in row m of the database, while the second received locally uniqueattribute may match a value in row n of the database. Here, additionalinferences may need to be made in order to determine the identity of thelocal base station. In this case, the database may be further updated todetermine what the first and second locally unique attributes should bein both rows m and n. In some cases, error checking may be performed tosee if locally unique attributes are mismatched and adjust accordingly.

Similarly, a number of inferences may be made to determine the identityof the local base station using at least the locally unique attributes.Other kinds of data, either existing in the database or from thereceived data, may be used to find various connections to help concludewhat the local base station may be. For example, the inferences may bebased on the received PF and/or CPID values. additional mapping may beused, where knowledge of the location of one recently used base stationnarrows the possibilities of the next used base station, based onproximity to the recently used base station. This knowledge may becombined with knowledge of the received PF and/or CPID values and adetermination may be made as to what is likely to be the local basestation. Similarly, these connections could be PF and CPID values thatsuggest nearby base stations, the locations of which could suggest othernearby stations, and so on until a CID value for the local base stationmay be determined. For example, referring to FIG. 5C, if a user starteda call on a mobile device in range of a base station with CPID of 71 andPF 10055 (71, 10055), and the call is handed over to (103, 10104), aglobally unique ID 0x210a95e can be inferred.

Because inferences may be made almost an unlimited number of times, thechain or number of inferences may be “cut off” or stopped by somethreshold criteria. For example, a maximum number of inferences to bemade may be specified. If a determination of the local base stationcannot be made by the set number of threshold inferences, then it may bedetermined that no match may be found.

At block 616, if it is determined that no values in the database matchthe received locally unique attributes from block 612, or that no matchin the database is found after conducting the maximum number ofinferences from block 614, then embodiments may perform an exhaustivesearch to identify the local base station. Performing the exhaustivesearch may be consistent with conventional techniques for searching forterrestrial base stations, which may consume more power and time thanthrough other means provided in this disclosure.

Many embodiments may be made in accordance with specific requirements.For example, customized hardware might also be used, and/or particularelements might be implemented in hardware, software (including portablesoftware, such as applets, etc.), or both. Further, connection to othercomputing devices such as network input/output devices may be employed.

Having described multiple aspects of improving signal acquisition timeof a base station, an example of a computing system in which variousaspects of the disclosure may be implemented will now be described withrespect to FIG. 7. According to one or more aspects, a computer systemas illustrated in FIG. 7 may be incorporated as part of a computingdevice, which may implement, perform, and/or execute any and/or all ofthe features, methods, and/or method steps described herein. Forexample, computer system 700 may represent some of the components of ahand-held device. A hand-held device may be any computing device with aninput sensory unit, such as a wireless receiver or modem. Examples of ahand-held device include but are not limited to video game consoles,tablets, smart phones, televisions, and mobile devices or mobilestations. In some embodiments, the system 700 is configured to implementany of the methods described above. FIG. 7 provides a schematicillustration of one embodiment of a computer system 700 that can performthe methods provided by various other embodiments, as described herein,and/or can function as the host computer system, a remotekiosk/terminal, a point-of-sale device, a mobile device, a set-top box,and/or a computer system. FIG. 7 is meant only to provide a generalizedillustration of various components, any and/or all of which may beutilized as appropriate. FIG. 7, therefore, broadly illustrates howindividual system elements may be implemented in a relatively separatedor relatively more integrated manner.

The computer system 700 is shown comprising hardware elements that canbe electrically coupled via a bus 705 (or may otherwise be incommunication, as appropriate). The hardware elements may include one ormore processors 710, including without limitation one or moregeneral-purpose processors and/or one or more special-purpose processors(such as digital signal processing chips, graphics accelerationprocessors, and/or the like); one or more input devices 715, which caninclude without limitation a camera, wireless receivers, wirelesssensors, a mouse, a keyboard and/or the like; and one or more outputdevices 720, which can include without limitation a display unit, aprinter and/or the like. In some embodiments, the one or more processor710 may be configured to perform a subset or all of the functionsdescribed above with respect to FIG. 6. The processor 710 may comprise ageneral processor and/or and application processor, for example. In someembodiments, the processor is integrated into an element that processesvisual tracking device inputs and wireless sensor inputs.

The computer system 700 may further include (and/or be in communicationwith) one or more non-transitory storage devices 725, which cancomprise, without limitation, local and/or network accessible storage,and/or can include, without limitation, a disk drive, a drive array, anoptical storage device, a solid-state storage device such as a randomaccess memory (“RAM”) and/or a read-only memory (“ROM”), which can beprogrammable, flash-updateable and/or the like. Such storage devices maybe configured to implement any appropriate data storage, includingwithout limitation, various file systems, database structures, and/orthe like.

The computer system 700 might also include a communications subsystem730, which can include without limitation a modem, a network card(wireless or wired), an infrared communication device, a wirelesscommunication device and/or chipset (such as a Bluetooth® device, an802.11 device, a WiFi device, a WiMax device, cellular communicationfacilities, etc.), and/or the like. The communications subsystem 730 maypermit data to be exchanged with a network (such as the networkdescribed below, to name one example), other computer systems, and/orany other devices described herein. In many embodiments, the computersystem 700 will further comprise a non-transitory working memory 735,which can include a RAM or ROM device, as described above.

The computer system 700 also can comprise software elements, shown asbeing currently located within the working memory 735, including anoperating system 740, device drivers, executable libraries, and/or othercode, such as one or more application programs 745, which may comprisecomputer programs provided by various embodiments, and/or may bedesigned to implement methods, and/or configure systems, provided byother embodiments, as described herein. Merely by way of example, one ormore procedures described with respect to the method(s) discussed above,for example as described with respect to FIG. 6, might be implemented ascode and/or instructions executable by a computer (and/or a processorwithin a computer); in an aspect, then, such code and/or instructionscan be used to configure and/or adapt a general purpose computer (orother device) to perform one or more operations in accordance with thedescribed methods.

A set of these instructions and/or code might be stored on acomputer-readable storage medium, such as the storage device(s) 725described above. In some cases, the storage medium might be incorporatedwithin a computer system, such as computer system 700. In otherembodiments, the storage medium might be separate from a computer system(e.g., a removable medium, such as a compact disc), and/or provided inan installation package, such that the storage medium can be used toprogram, configure and/or adapt a general purpose computer with theinstructions/code stored thereon. These instructions might take the formof executable code, which is executable by the computer system 700and/or might take the form of source and/or installable code, which,upon compilation and/or installation on the computer system 700 (e.g.,using any of a variety of generally available compilers, installationprograms, compression/decompression utilities, etc.) then takes the formof executable code.

Substantial variations may be made in accordance with specificrequirements. For example, customized hardware might also be used,and/or particular elements might be implemented in hardware, software(including portable software, such as applets, etc.), or both. Further,connection to other computing devices such as network input/outputdevices may be employed.

Some embodiments may employ a computer system (such as the computersystem 700) to perform methods in accordance with the disclosure. Forexample, some or all of the procedures of the described methods may beperformed by the computer system 700 in response to processor 710executing one or more sequences of one or more instructions (which mightbe incorporated into the operating system 740 and/or other code, such asan application program 745) contained in the working memory 735. Suchinstructions may be read into the working memory 735 from anothercomputer-readable medium, such as one or more of the storage device(s)725. Merely by way of example, execution of the sequences ofinstructions contained in the working memory 735 might cause theprocessor(s) 710 to perform one or more procedures of the methodsdescribed herein, for example methods described with respect to FIG. 6.

The terms “machine-readable medium” and “computer-readable medium,” asused herein, refer to any medium that participates in providing datathat causes a machine to operate in a specific fashion. In an embodimentimplemented using the computer system 700, various computer-readablemedia might be involved in providing instructions/code to processor(s)710 for execution and/or might be used to store and/or carry suchinstructions/code (e.g., as signals). In many implementations, acomputer-readable medium is a physical and/or tangible storage medium.Such a medium may take many forms, including but not limited to,non-volatile media, volatile media, and transmission media. Non-volatilemedia include, for example, optical and/or magnetic disks, such as thestorage device(s) 725. Volatile media include, without limitation,dynamic memory, such as the working memory 735. Transmission mediainclude, without limitation, coaxial cables, copper wire and fiberoptics, including the wires that comprise the bus 705, as well as thevarious components of the communications subsystem 730 (and/or the mediaby which the communications subsystem 730 provides communication withother devices). Hence, transmission media can also take the form ofwaves (including without limitation radio, acoustic and/or light waves,such as those generated during radio-wave and infrared datacommunications).

Common forms of physical and/or tangible computer-readable mediainclude, for example, a floppy disk, a flexible disk, hard disk,magnetic tape, or any other magnetic medium, a CD-ROM, any other opticalmedium, punchcards, papertape, any other physical medium with patternsof holes, a RAM, a PROM, EPROM, a FLASH-EPROM, any other memory chip orcartridge, a carrier wave as described hereinafter, or any other mediumfrom which a computer can read instructions and/or code.

Various forms of computer-readable media may be involved in carrying oneor more sequences of one or more instructions to the processor(s) 710for execution. Merely by way of example, the instructions may initiallybe carried on a magnetic disk and/or optical disc of a remote computer.A remote computer might load the instructions into its dynamic memoryand send the instructions as signals over a transmission medium to bereceived and/or executed by the computer system 700. These signals,which might be in the form of electromagnetic signals, acoustic signals,optical signals and/or the like, are all examples of carrier waves onwhich instructions can be encoded, in accordance with variousembodiments of the invention.

The communications subsystem 730 (and/or components thereof) generallywill receive the signals, and the bus 705 then might carry the signals(and/or the data, instructions, etc. carried by the signals) to theworking memory 735, from which the processor(s) 710 retrieves andexecutes the instructions. The instructions received by the workingmemory 735 may optionally be stored on a non-transitory storage device725 either before or after execution by the processor(s) 710. Memory 735may contain at least one database according to any of the databases andmethods described herein. Memory 735 may thus store any of the valuesdiscussed in any of the present disclosures, including FIGS. 5C and 6and related descriptions.

The methods described in FIG. 6 may be implemented by various blocks inFIG. 7. For example, processor 710 may be configured to perform any ofthe functions of blocks in diagram 600. Storage device 725 may beconfigured to store an intermediate result, such as a globally uniqueattribute or locally unique attribute discussed within any of blocksmentioned herein. Storage device 725 may also contain a databaseconsistent with any of the present disclosures. The memory 735 maysimilarly be configured to record signals, representation of signals, ordatabase values necessary to perform any of the functions described inany of the blocks mentioned herein. Results that may need to be storedin a temporary or volatile memory, such as RAM, may also be included inmemory 735, and may include any intermediate result similar to what maybe stored in storage device 725. Input device 715 may be configured toreceive wireless signals from satellites and/or base stations accordingto the present disclosures described herein. Output device 720 may beconfigured to display images, print text, transmit signals and/or outputother data according to any of the present disclosures.

The methods, systems, and devices discussed above are examples. Variousembodiments may omit, substitute, or add various procedures orcomponents as appropriate. For instance, in alternative configurations,the methods described may be performed in an order different from thatdescribed, and/or various stages may be added, omitted, and/or combined.Also, features described with respect to certain embodiments may becombined in various other embodiments. Different aspects and elements ofthe embodiments may be combined in a similar manner. Also, technologyevolves and, thus, many of the elements are examples that do not limitthe scope of the disclosure to those specific examples.

Specific details are given in the description to provide a thoroughunderstanding of the embodiments. However, embodiments may be practicedwithout these specific details. For example, well-known circuits,processes, algorithms, structures, and techniques have been shownwithout unnecessary detail in order to avoid obscuring the embodiments.This description provides example embodiments only, and is not intendedto limit the scope, applicability, or configuration of the invention.Rather, the preceding description of the embodiments will provide thoseskilled in the art with an enabling description for implementingembodiments of the invention. Various changes may be made in thefunction and arrangement of elements without departing from the spiritand scope of the invention.

Also, some embodiments were described as processes depicted as flowdiagrams or block diagrams. Although each may describe the operations asa sequential process, many of the operations can be performed inparallel or concurrently. In addition, the order of the operations maybe rearranged. A process may have additional steps not included in thefigure. Furthermore, embodiments of the methods may be implemented byhardware, software, firmware, middleware, microcode, hardwaredescription languages, or any combination thereof. When implemented insoftware, firmware, middleware, or microcode, the program code or codesegments to perform the associated tasks may be stored in acomputer-readable medium such as a storage medium. Processors mayperform the associated tasks.

Having described several embodiments, various modifications, alternativeconstructions, and equivalents may be used without departing from thespirit of the disclosure. For example, the above elements may merely bea component of a larger system, wherein other rules may take precedenceover or otherwise modify the application of the invention. Also, anumber of steps may be undertaken before, during, or after the aboveelements are considered. Accordingly, the above description does notlimit the scope of the disclosure.

Various examples have been described. These and other examples arewithin the scope of the following claims.

What is claimed is:
 1. A method for improving time to acquire anidentity of a base station by a mobile station, the method comprising:requesting data containing a globally unique attribute of the basestation, a first locally unique attribute of the base station, and asecond locally unique attribute of the base station; receiving data inresponse to the request, the data containing at least the first locallyunique attribute and the second locally unique attribute, wherein thefirst locally unique attribute is a midamble index present in a timeslot of a subframe, the midamble index being present between two datapayload portions within the time slot of the subframe; determining thatthe data did not contain the globally unique attribute; and acquiringthe identity of the base station based at least in part on the firstlocally unique attribute and the second locally unique attribute.